Oil is generally utilized to lubricate moving parts in mechanical systems, such as engines, transmissions, and hydraulics in vehicles. Contaminants are not originally present in the oil but are by-products of wear and corrosion in these systems. Metal particulates are formed through abrasion or chemical corrosion and cause further deterioration of internal parts. Normal operation causes oxidation, nitration, and sulfation, but the introduction of additional elements or compounds into the oil accelerates the accumulation of metal particles from abrasion and corrosion. The lubricant filters are designed to remove larger size particulates from oil. However, this leaves the majority of smaller contaminants free to further affect the equipment, especially the nonmetallic components such as pump diaphrams, gaskets and seals, fluid lines, etc.
Concentrations of water in oil affect systems differently, i.e., some systems are of little concern unless above a certain concentration while other systems may be effected with the slightest trace of water. Small amounts of water come from primarily water vapor in the atmosphere, and larger amounts may be due to water leaks, which could damage equipment.
Ethylene glycol is the main component used in anti-freeze products. A significant leak could also damage equipment. Thus, contaminants in oil such as ethylene glycol, fuel, silicon, and soot and other chemicals are also concerns.
Oil analysis provides a method of monitoring wear trends on moving parts of virtually any system or mechanical device. This allows identifying changes from normal wear patterns and thereby predicts progressive damage-type failures. The composition of foreign materials in oil can be determined by a variety of techniques, such as infrared spectrometry, optical emission spectrometry, x-ray fluorescence, etc.
Accurate oil analysis has been provided mainly in a laboratory setting. A system utilized in a laboratory is disclosed in U.S. Pat. No. 3,526,127, issued to Sarkis on Sep. 1, 1970. Sarkis is a semi-automated oil analysis system for a laboratory which utilizes a metal content testing device, a viscometer and an infrared absorbing device. These testing devices transmit their results to a computer which stores reference limits, compares the tested values to the reference limits, and provides evaluation, reporting and trending of oil for various types of engines. An oil sample is separated into three different containers; one container of oil is read by the metal electrometer to determine the concentration of metals; a second container of oil is measured by the viscometer; and a third container of oil is measured by the infrared analyzer to determine contents of water and glycol, and determine oil degradation. The results are sent to a computer which stores the reference information of viscosity, metal content, and infrared characteristics.
It is desirable to have a shop-level or on-site machine that can comprehensively evaluate the condition of an engine, transmission, gear box, or other oil source through the measurement of microscopic wear debris and dissolved contaminants in the equipment's lubricating oil.